This project aims to identify brain areas salient to known deficits in the cognitive performance of schizophrenics. Psychophysical tasks known to show performance deficits in schizophrenia, and having adequate reliability and familial similarity will be studied with positron emission tomography with 18 F-2-deoxyglucose (FDG). The tasks include the Wisconsin card sort, smooth pursuit pendulum eye tracking, reaction time, pursuit rotor performance, and the continuous performance test. Adult normal controls will be screened for medical and psychiatric illness by structured schedule (SADS-L), drug use by urine screen, and for family history of psychiatric illness by interview. Sixteen subjects will perform each task during FDG uptake. Following uptake of FDG and labeling of brain structures in the psychophysical laboratory, the NeuroEcat scanner (7.6 mm in plane and 11.6 mm axial resolution) will obtain slice images to assess the metabolic rate of glucose (micromoles glucose/100g/minute). All subjects will receive MRI scans using the same individually fitted thermoplastic head holder to allow specific structures to be identified by reference to the anatomic image. In the first analysis, each group will be compared with a naive reference group (already obtained) viewing continuous performance test stimuli, but with instructions only to use the stimuli as a fixation spot. Brain areas with significantly elevated metabolic rates common to the five tasks will be sought to identify structures key to performance deficits in schizophrenia. In a second analysis, the relationship between task performance and regional metabolic rate will be assessed with correlation coefficients. In the second phase of the project, the task showing the most reliable metabolic rate elevations in structures activated by all tasks, will be tested in a group of unmedicated patients with schizophrenia and a new group of normals for replication.